Atmospheric and
Oceanic Sciences

Weekly Weather Event -Week of June 7th

June 12, 2021

It has been a dry June, with the U.S. Drought Monitor reporting that 45% of the continental United States under drought conditions as of June 8th. Compared to the report released June 1st, drought and abnormally dry conditions have overall worsened as the month has progressed. This expansion has largely been a result of above average temperatures in the High Plains and upper Midwest; conditions have been 9-12 degrees warmer combined with lower than average precipitation. The Northeast also experienced above average temperatures, contributing to additional expansion of abnormally dry and drought conditions.

Regionally, the worst drought conditions continue in the West with 27% of the land under an extreme drought. Lake Mead, the reservoir formed by the Hoover Dam on the Colorado River, has reached historically low water levels and reached its lowest level since the damming of the river in 1935. Water levels are expected to continue to decline until November per the U.S Bureau of Reclamation.

The U.S. Drought Monitor is divided into five distinct categories of drought conditions ranging from D0 to D4. These stages are determined by a number of drought monitoring statistics and models, including soil moisture models and weekly streamflow. It is important to note that the U.S. Drought Monitor is best used as a big-picture look and may not accurately reflect local conditions.

D0 is the abnormally dry stage, and possible impacts include: short-term slowing of planting and growth of agricultural plants, and some lingering water deficits after the dry period has passed.

D1 is the moderate drought stage, and possible impacts include: damage to crops and pastures, lowered water reserves, and voluntary water-use restrictions requested.

D2 is the severe drought stage, and possible impacts include: likely agricultural losses, water shortages common, and water restrictions imposed.

D3 is the extreme drought stage, and possible impacts include major agricultural losses and widespread water shortages or restrictions.

Finally, D4 is the exceptional drought stage, and possible impacts include widespread agricultural losses and water shortages worsening to water emergencies.